Lupeni is a mining city located in the Jiu Valley within Hunedoara County, Romania. Situated in the historical region of Transylvania, it stands as one of the oldest and largest cities in the Jiu Valley area.
The city is positioned on the banks of the Western Jiu River at an elevation ranging between 630 metres (2,070 ft) and 760 metres (2,490 ft). It is located approximately 18 kilometres (11 mi) from Petroșani via the DN66A road and 114 km (71 mi) from Deva.